Objectives: (1) To extend the theoretical and empirical differentiation of the concept of locus of control, especially as it applies to the inquiry behaviors of elementary students classified as externals. (2) To compare and describe the ways in which children classified either as externals or as internals conduct two simple science investigations that differ in level of structure and in which cue selection and utilization is under the control of the subject, i.e., to examine the problem solving strategies of externals and internals when confronted with two investigations which differ in level of structure but not in conceptual complexity. (3) To determine whether there in an interaction between level of task structure and locus of control in predicting performance. (4) To determine whether the verbal language employed by externals to discuss their procedures and findings differs in any significant way from that employed by internals. (5) To examine how externals and internals compare on certain task-related outcome variables: (a) acquisition and retention of information; (b) task persistence; (c) type and number of questions asked; (d) quantity and quality of explanations offered; and (e) occurrence and quality of statements that tie inferences to evidence. (6) To compare the predictive validity of three locus of control measures. (7) To obtain the composite factor structure for the three locus of control measures and to determine by multiple regression techniques the efficacy of the factors as predictors of performance. The study will seek to answer such question as the following: 1) In what way do the problem solving behaviors of children classified as externals on a locus of control measure differ from the behaviors of those categorized as internals when both are confronted with two science investigations that differ in level of structure? 2) Is there an interaction between levels of task structure and locus of control in predicting performance? 3) Does the verbal language employed by externals to discuss observations, to make inferences and to ask questions differ in any significant way from the language used by internals?